In a computed tomography (CT) imaging system or scanner, an x-ray tube is commonly utilized to generate a high-intensity beam of x-rays for irradiating an anatomical region of interest (ROI) within a patient. In utilizing the x-ray tube in this manner, the CT scanner is able to ultimately generate one or more computer images of the patient's ROI for examination and medical diagnosis. During such operation of the CT scanner, the x-ray tube is generally supplied with large amounts of electrical power that are converted into heat, which thereby causes the x-ray tube to get hot. To prevent overheating and burnout of the x-ray tube and any electrical circuitry or mechanical components proximate thereto, a liquid for cooling the x-ray tube is typically passed through the housing in which the x-ray tube is situated. Typically, the liquid is a heat-absorbing “cooling liquid” such as, for example, a dielectric oil.
To systematically pass cooling liquid through the x-ray tube housing, the housing is connected within a fluid flow circuit that circulates the liquid through the housing. The fluid flow circuit, in addition to the x-ray tube housing, usually includes a heat exchanger assembly, a centrifugal pump, and an accumulator. In general, the x-ray tube housing, the heat exchanger assembly, the centrifugal pump, and the accumulator are all interconnected together so as to establish a substantially closed liquid-circulation system with little to no air or gas present therein. The heat exchanger assembly, first of all, generally serves to remove and dissipate heat from the cooling liquid after the liquid has passed through the x-ray tube housing and absorbed heat from the x-ray tube. Once the cooling liquid has been sufficiently cooled by the heat exchanger assembly, the centrifugal pump then serves to pump and re-circulate the cooling liquid back through the x-ray tube housing so as to again draw heat from the x-ray tube. The accumulator, last of all, generally serves to ensure that the cooling liquid is physically accommodated within the fluid flow circuit in a volume-fitted manner and that the overall pressure within the circuit does not significantly increase during expansion of the cooling liquid. The accumulator accomplishes such by elastically adapting to changes in the overall volume of the cooling liquid within the fluid flow circuit, both during volumetric expansion of the liquid when it is hot and during volumetric contraction of the liquid when it is cold. Elastically adapting to volumetric changes in the cooling liquid in this manner is conventionally referred to as “volume compensation” or simply “compensation.” To achieve such compensation, the accumulator itself typically includes a sturdy outer housing and an internal membrane protected therein. The internal membrane, in addition to being elastic and expandable, is characteristically impermeable and may comprise, for example, a rubber bladder, diaphragm, or bellows. The maximum supplemental volume provided by such a membrane or bladder when filled with hot liquid and fully expanded is conventionally referred to as its “compensation value.”
Per modern convention, the x-ray tube housing, heat exchanger assembly, centrifugal pump, and accumulator are all generally interconnected within the fluid flow circuit by a series of hoses and interlocking couplers. The couplers typically include quick-disconnect (QD) features and internal automatic shut-off valves. Equipped as such, a mating pair of couplers can therefore be easily connected, disconnected, or re-connected by a serviceman in the field without leaking large amounts of cooling liquid from the fluid flow circuit and without introducing large amounts of air into the circuit. In this way, any necessary servicing, maintenance, removal, or replacement of the x-ray tube housing, heat exchanger assembly, centrifugal pump, or accumulator is generally facilitated.
Despite being interconnected in the above-described manner, sometimes a significant amount of cooling liquid is still lost or inadvertently leaked from the fluid flow circuit when servicing one or more of the above-mentioned circuit components. In particular, though the circuit's couplers are typically equipped with automatic shut-off valves, cooling liquid is nevertheless often leaked via one or more of these couplers as they are disconnected and re-connected during service. If such a loss of cooling liquid is not properly corrected, the fluid flow circuit may suffer a corresponding reduction in its overall cooling capability. As a result, overheating and burnout of the x-ray tube as well as nearby electrical components may occur.
To prevent such potential consequences, a controlled amount of cooling liquid must generally be newly introduced or added into the fluid flow circuit so that the cumulative amount of cooling liquid present within the circuit is restored up to a predetermined proper level. Such a predetermined proper level of cooling liquid is often conventionally referred to as the “compensation level,” for the accumulator's bladder in the fluid flow circuit can successfully compensate for (i.e., physically accommodate) any subsequent volumetric expansion of the cooling liquid during operation if the initial cumulative amount of liquid in the circuit does not exceed this predetermined limit level. Thus, when adding cooling liquid to the fluid flow circuit, care must be exercised so as to not add too much liquid and exceed this predetermined limit level, for the expandable bladder of the accumulator may consequently rupture or burst during subsequent operation when the liquid is hot and expanded, thereby potentially causing the spillage of hot oil from the CT scanner. Ultimately, by replenishing the fluid flow circuit with enough cooling liquid so that the cumulative amount of liquid within the circuit is restored back up to compensation level, the circuit's optimum cooling capability is thereby restored and the risk of rupturing the accumulator's bladder is thereby minimized as well. Having to newly introduce or add such a controlled amount of cooling liquid into the fluid flow circuit, however, is often a laborious and undesirably time-consuming task. In particular, according to current convention, a serviceman must generally go through an iterative multi-step fluid insertion and calibration process to ensure the transfer of an appropriate amount of cooling liquid into the fluid flow circuit. Furthermore, since fluid spills while carrying out such a liquid replenishment process are not uncommon, the process is oftentimes rather messy as well.
In addition to sometimes losing cooling liquid, sometimes a significant amount of air is inadvertently introduced into the fluid flow circuit when servicing one or more of the above-mentioned circuit components. In particular, though the circuit's couplers are typically equipped with automatic shut-off valves, air is nevertheless often ingested via one or more of these couplers as they are disconnected and re-connected during service. If such ingestion of air into the fluid flow circuit is not properly corrected, certain consequences may occur. For example, with the introduction of air into the fluid flow circuit, hot pockets of air are apt to develop and be circulated through the circuit during operation, thereby reducing the circuit's overall cooling capability. As a result, highly localized heating and burnout of the x-ray tube as well as nearby electrical components may occur. In addition, artifacts may begin to appear in CT scanner images, thereby reducing scanner image resolution and quality. Furthermore, with air pockets circulating through the fluid flow circuit, the centrifugal pump is likely to begin “choking” and operating less efficiently, and may even incur damage due to cavitation.
To prevent such potential consequences, various different methods have heretofore been proposed for preventing the inadvertent ingestion of air and/or removing air that has already been ingested into a fluid flow circuit. Such methods proposed to date, however, typically involve numerous steps and are characteristically labor intensive. Consequently, the methods are often rather time-consuming and highly inefficient overall. Furthermore, since fluid spills when implementing such methods are not uncommon, the methods are frequently quite messy as well.
In light of the above, there is a present need in the art for a simple tool that is utile for transferring controlled amounts of liquid into and from a fluid flow circuit with minimal spillage and without introducing significant amounts of air into the circuit. For some applications, it is preferable that such a tool also be utile for removing any air or gas bubbles that may already exist in the fluid flow circuit.